IIT Guwahati - Indian Institute of Technology

Old IITs are the best. They enhance your personality.

Off course IIT Guwahati because in IIT you will get more opportunities, better infrastructure, international platform, tech fest, faculty, and placement. If you are getting CSE in IIIT Hyderabad, then without doubt go for IIIT Hyderabad.

Hi,
Kindly predict your college in this college predictor. JEE Mains rank predictor is an online tool which predicts the candidate's rank range and probable colleges based on the difficulty level of the examination, average marks scored in JEE Main and seats available in IITs, NITs, GFTIs and other SFTIs. The rank predicted might not be accurate but it certainly does give an idea to the aspirant. Know your college admission chances based on your JEE Mains rank, home state, caste, gender, etc. here:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor

Yes you can and I suggest you should try it.

Yes, if you will get more than 8.5 GPA, then you can.

You have not told us about the rank you obtained, So, we cannot answer correctly. However, as per the last year trends, the UCEED score above 167 can be safe for admission in IITs.